The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
Previously, the semiconductor industry utilized various methods and structures to form vertical metal oxide semiconductor (MOS) transistors. These vertical transistors generally utilized a doped portion of the semiconductor substrate to form a source contact region for the transistor and formed a body region of the transistor within the source contact region. A source electrode usually was formed to electrically contact both the source region and the body contact region. An example of such a vertical transistor is disclosed in U.S. Pat. No. 4,960,723 which issued to Robert B. Davies on Oct. 2, 1990 which is hereby incorporated herein by reference. The resistance from the source electrode to the source region and the body region often affected the performance of the transistor. The greater the resistance the lower the performance. In one implementation, an opening was formed through the source region to expose a portion of the body contact region and a metal was formed on both the source region and the body contact region to function as the source electrode. Often, there was a high resistance to either the source region or the body contact region.
Accordingly, it is desirable to have a method and structure that provides a low resistance current path and a low contact resistance to both the source region and body region of a transistor and that provides a low resistance contact to two adjacent differently doped regions.
For simplicity and clarity of illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain N-channel or P-Channel devices, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. For clarity of the drawings, doped regions of device structures are illustrated as having generally straight line edges and precise angular corners. However, those skilled in the art understand that due to the diffusion and activation of dopants the edges of doped regions are generally not straight lines and the corners are not precise angles.